The Sunday newspaper that is sold in many metropolitan areas typically comes bundled with a number of advertising and other inserts. The distribution system that places these in the hands of the reader is complex, and includes a number of specialized machines and assembly lines. At one stage, a variety of inserts may be placed into a folder called a package, and at another stage, the package is transported along a conveyor system to a place where these folders are stacked and bundled together for shipment to distributors. The lines used to accomplish all of this work are expensive and must work at a high rate of speed to justify their substantial investment of capital. Errors at any point along the line can result in expensive down time.
One such error can occur during the transfer of the package of inserts from an overhead conveyor system to a stacker machine where they are stacked and bound into a pile. It is known to affect this transfer via a rotary wheel of gripping devices known as a gripper drum. Typically, the package is gripped at its free ends by a gripper and transported via overhead conveyor to a point just above one of the grippers of the gripper drum, at which point the overhead gripper releases its grip, allowing the package to fall a short distance to the rotating grippers of the gripper drum, where they are gripped at their opposite, folded ends and rotated into position above a conveyor belt. Once there, the rotating grippers release their grip, and the packages fall onto a conveyor for transport to a stacker machine.